Pile pressing device

Abstract

A device for pressing a pile of sheets in a feeding unit or station including a vertically movable pressing carriage with a pressing device being guided in a vertical path formed by rails and a groove provided in a front surface of a gauge of the feeding unit. The pressing device includes a sensing arrangement acting on a switch connected in a control circuit for a pneumatic drive so that when introducing an additional batch of sheets into the feeding station the sensing device actuates the pneumatic piston to retract the pressing device to provide clearance for the additional batch.

I claim: 
     
       1. A device for pressing a pile of sheets in a feeding station, said feeding station having conveyor means with continuous belts for transporting a bottom sheet in a pile of sheets and means for preventing passage of more than one sheet at a time from the bottom of the pile, said means including a gauge with a lower edge, support means including a support member for mounting the gauge in the feeding station with the lower edge spaced above the surface of the belt of the conveyor by the required distance, said device comprising a pressing carriage; a vertical path defined by at least one vertically extending rail mounted on the support member and a vertically extending groove on a surface of the gauge, said carriage having slide elements engaging the groove in each rail to guide the carriage along the vertical path; a pressing device mounted on said carriage including an infeed guide with an aperture; sensing means for determining contact with a batch of sheets being introduced to the pile including a switch mounted in said aperture of the infeed guide, a sensing plate and means for mounting the sensing plate on the infeed guide for pivotal movement into and out of contact with the switch; and drive means for moving the carriage along the vertical path including a pneumatic piston mounted on a support having a piston rod attached to the infeed guide, control means including setting means for adjusting the pressing force of the pressing unit, drive means for commanding the vertical shifting and central means for checking the elevation and lowering speeds as the pneumatic fluid is applied to the piston so that the pressing device maintains a constant pressure on the stack in the feeding station and, when adding an additional batch of sheets to the pile, the sensing means is tripped causing a retraction of the pressing device to provide clearance for inserting of the batch of sheets onto the pile. 
     
     
       2. A device according to claim 1, wherein the support means for mounting the gauge includes an arm secured to the support member, the other end of said arm being adjustably mounted on a cross-piece of the frame of the feeding station so that the device can be adjustably positioned along the transverse direction of the feeding station. 
     
     
       3. A device according to claim 1, wherein the sensing plate of the sensing means has two lateral flanges, each of said flanges having an adjustable stop to limit the direction of movement of the plate in one pivotal direction. 
     
     
       4. A device according to claim 1, wherein a pneumatic circuit for the drive means includes couplings for connecting a drive means of another device to act concurrently therewith.